Geographic Range

The blacktip shark is widespread in all tropical and subtropical continental waters. These waters include: the Western Atlantic Ocean (including the Caribbean Sea), the Eastern Atlantic, the Indo-West Pacific (Southeast Asia and Australian waters), Central Pacific (Hawaiian Islands), Eastern Pacific (Californian coast) as well as in the Red Sea (Compagno, 1984).

Habitat

Blacktip sharks are common tropical, warm-temperate, inshore and offshore sharks (Stafford-Deitsch, 1987). They are often found on or near the continental and insular shelves. Blacktips are also commonly found close to the shore, in estuaries as well as river mouths (Stafford-Deitsch, 1987). They are also found in shallow muddy bays, mangrove swamps of high salinity, lagoons, coral reef dropoffs and in areas found far offshore (Compagno, 1984). Blacktip sharks usually stay in waters shallower than thirty meters and can handle freshwater environments but are rarely found in them (Compagno, 1984).

Physical Description

Blacktip sharks are relatively large sharks, grey in color with a long pointed snout. They have small eyes. The teeth are narrow, erect and narrow-cusped serrated upper anterolatheral teeth (Compagno, 1984). Blacktips lack an interdorsal ridge and have relatively large pectoral fins (Compagno, 1984). The first dorsal fin is large with a black tip on the rear. The second dorsal fin is much smaller yet contains a black tip as well. Usually, most fins on the black tip sharks contain black tips (with the exception of the tail-fin) (Stafford-Deitsch, 1987).

Reproduction

Female blacktips are viviparous and contain a yolk-sac placenta. The number of offspring per litter ranges from 1-10 (usually 4-7)(Compagno, 1984).

Gestation of the young lasts anywhere from 10-12 months (Compagno, 1984). The young are born in late spring or early summer. Pregnant females move inshore to drop their young in nursery and pupping grounds. Young are believed to be produced in alternate years by each female blacktip (Compagno, 1984).

Lifespan/Longevity

Behavior

Blacktip sharks fast-swimming sharks that often travel in schools. They are active and usually found in near surface waters of shallower marine areas (Taylor, 1993). Blacktips are often confused with related spinner sharks because of their feeding method. A blacktip often shoots itself through the surface water and can rotate up to three times around its axis snapping in all directions in hope of attaining food (Compagno, 1984).

Blacktips, at times, can be an aggressive species which approaches swimmers and divers. Aside from this behavior, very few blacktip attacks on humans have been documented. Moreover, blacktips are regarded as relatively harmless sharks.

Economic Importance for Humans: Positive

Blacktips are used as a food source for human consumption. Their hide can be used to make leather goods. Due to the high vitamin content of the liver oil, it is used for vitamins. The dead carcasses can also be used as fish meal (Compagno, 1984).

Economic Importance for Humans: Negative

There have been instances of blacktip attacks on humans, though these instances are very rare. It is also common for blacktips to get caught in shrimp trawl nets (Compagno, 1984; Taylor, 1993).

Conservation Status

As is true with many species of shark, blacktips have experienced reductions in their numbers. This is due to overfishing and killing of the shark. The blacktip however is still a relatively abundant species of shark and is currently not protected by federal law.

Contributors

Glossary

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

coastal

the nearshore aquatic habitats near a coast, or shoreline.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

reef

structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

References

Copagno, L. 1984. Sharks of the World. Rome, Italy: United Nations Development Programme Food and Agriculture Organization of the United Nations.

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This material is based upon work supported by the
National Science Foundation
Grants DRL 0089283, DRL 0628151, DUE 0633095, DRL 0918590, and DUE 1122742. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services.